Pipe wiper cutter



J. c. BALLAGH PIPE WIPER CUTTER Filed Dec- 1944 Patented May 23, 1950 UNITED 'QFFF P 3 Glaims.

My lnverrtionrelates=to pipe wiper cutters+that is, to-cutting devices which are particularly adapted to cut out the central portions of the pipe wiper disclosed in my previous Patent No.

12,272,395, issued February 10, 1942, in order to ..may appear hereinaftenreference is directed to the accompanying drawings, "in which:

Fig. 1 is a perspective view of my pipe wiper cutter.

Fig. 2 is a longitudinal sectional View thereof taken substantially through 22 of Fig. 1, with portions as shown in elevation.

Fig. 3 is an enlarged sectional view taken through 3-3 of Fig. 4, showing the angular relation of the cutting knife to the tangent of the circle in which it travels.

Fig. 4 is an enlarged sectional view thereof, taken through 4-4 of Fig. 3, showing the cutting blade in elevation.

Fig. 5 is a further enlarged transverse sectional view through the knife blade taken through 5-5 of Fig. 3.

My pipe wiper cutter includes a base plate I, which may be in the form of a flat rectangular casting supported by marginal rims 2. The center of the base plate is provided with a circular depression 3 having a centered threaded socket 4 therein. A journal sleeve 5 is secured in the socket and is provided with a journal bore at right angles to the upper face of the base plate I. Fitted within the depression 3 around the journal sleeve 5 is a backing pad 6 preferably formed of rubber; in fact, the backing pad may be a central section cut from one of my pipe wipers referred to in the above mentioned patent and which will be described hereinafter. The upper end of the sleeve 5 may be enlarged to form a shoulder for retaining the backing pad 6 in place.

A post I is journaled in the sleeve 5 and capable of axial movement therein. The post is provided with a transverse opening which slidably receives an arm 8 preferably 'Iflattened an 'one side so that a set screw QfEXtBHdiHg axially -into "the post I may :secure the Jam 28 against turning. One extremity .of "the arm .8 is mevided with an upwardly directe'd :Itrotatably mounted handle to so that the arm and sits shand-le may be rotated or cranked :ahoutithe :axis (of :thepostl.

Interposed in the arm 8 nearzthe handle :l:0:::ls a knife-supporting block i l. 'The block i'sjprovidedwith a slit l3 which 'is set at aislighlt angle designated A in Fig. 3, with respect to the tangent of the circle-describ'ed by the arm a. "ilherslit l3 extends to the center line or the arm adapted 'to '=be cons'tricted by means "of fclamping bolts "M. The slit [3 receives a knife :ibl'adeil-E which is -of uniform thickness. Ilihe protruding lower :portion "of the knife i blade curves rearwardly and downwardly aslindicated by :Mi, terminating at 'a point H rwhicheis located vertica'lly below the :medium lline of the arm .8 and is in a plane passing through the axis of the post I. The forward and rearward edges of the knife blade are rounded as shown best in Fig. 5, with the exception of a short portion l8 adjacent the point I! which is sharpened on the forward or curved side of the knife.

My pipe wiper designated 2|, is in the form of a large disc of rubber comprising a rim portion 22 which may be reinforced and relatively stiff, and a central portion which is more flexible and tapering slightly in thickness toward the center of the wiper. The wiper is provided with a central opening 23 adapted to fit around the upper end of the channel sleeve 5. Irrespective of the size of drill pipe or casing around which it is intended to employ the pipe wiper, its central opening 23 is initially of one diameter, namely, that which fits the journal sleeve 5. Spaced concentrically around the central opening 23 are a series of small ribs 24. These ribs correspond to the different sizes of drill pipes and casings with which it is intended to use the pipe wiper.

My pipe wiper cutter is employed as follows: The pipe wiper is placed over the sleeve 5 so that it rests on the base plate I and the backing pad 6. The post 1 is inserted and the arm 8 is adjusted until the knife blade I5 is positioned adjacent one of the ribs 24. The arm 8 is then rotated in the direction of the arrows shown in Figs. 1, 3 and 4, causing the sharpened end of the knife to cut into the pipe wiper. Only the relatively small sharpened portion I8 cuts the material of the pipe wiper. As the knife penetrates the wiper, the rounded forward edge above the sharpened portion l8 tends to spread the previously cut edges of the wiper and facilitate further cutting by the knife. The cutting action is also enhanced by reason of the slight angular relation between the plane of the knife blade and the tangent of the circle which it describes. It has been found that by the combination of the angularly positioned knife and the location of the sharpened portion I8 in a plane as nearly as possible coincident with a plane through the axis of the post 1, a particularly satisfactory clean cut may be readily made, even by an inexpert person.

Many other embodiments of the invention may be resorted to without departing from the spirit of the invention.

I claim:

1. A cutter adapted to trim to size a central opening in an annular pipe wiper, comprising: a base structure adapted to support a pipe Wiper; an upstanding post extending through the central portion of said pipe wiper; a radius arm overhanging said pipe wiper; a knife carried by said radius arm and engageable with said pipe wiper todescribe a circular cut on said pipe wiper; said knife being disposed at an acute angle with respect to the tangent of the circle described by said radius arm, the forward edge of said knife being sharpened for a distance which is small compared to the thickness of the pipe wiper, the Q remainder of the forward edge of the knife being rounded.

2. A cutter adapted to trim to size the opening in an annular pipe wiper comprising: a-rigid base structure defining a plane surface having a cen- 4 in said bearing member; an extensible radius arm carried by said shaft; a knife support incorporated in said radius arm; and a knife secured in said support and adapted to describe and cut circles in a pipe wiper resting On said base structure and backing disk.

3. A cutter adapted to trim to size the central opening in an annular pipe wiper comprising: a base structure adapted to support a pipe wiper; a knife support rotatable over said base and said pipe wiper; a knife carried by said support and adapted to describe and cut circles in said pipe wiper, said knife having a point formed at its lower end, and a portion of the leading edge of said knife being sharpened to a cutting edge, said portion extending upwardly from said point a distance less than the thickness of said pipe wiper, said cutting edge merging into a transversely rounded leading edge adapted to enter and spread the cut made by said cutting edge as cutting of said pipe wiper progresses.

JAMES C. BALLAGH..

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS umber Name Date 677,339 Comstock July 2, 1901 718,863 Norris Jan. 20, 1903 1,966,962 Horhorouny July 17, 1934 2,066,381 Albertson Jan. 5, 1937 2,134,069 Zimmerman Oct. 25, 1938 2,194,409 Stangohr Mar. 19, 1940 2,311,234 Krajnc Feb. 16, 1943 FOREIGN PATENTS Number Country Date 16,546 Great Britain of 1902 

